This invention relates in general to buoyant-wheel vehicles and, in particular, to an improved all terrain vehicle.
More specifically, but without restriction to the embodiments shown and described, this invention relates to an all terrain vehicle utilizing a segmented air-track crawler to support the vehicle for movement over various terrain.
Due to the wide variations of terrain over which it is necessary to transport materials and people, various vehicles have been developed for movement over difficult terrain. Such vehicles must be capable of movement over not just land surfaces, but also water and combinations thereof under varying conditions and situations For example, sand beaches, marshes, mud flats, peat bogs, water, whether deep, shallow, or weed infested, ice, which may be over or under water, or ground, which due to cyclic weather conditions can vary between clinging mud and frozen tundra are but some examples over which such vehicles must traverse
Supporting vehicles for movement over such difficult terrain can generally only be accomplished by the use of either an air-cushion vehicle or a buoyant-wheeled vehicle. While aircraft could certainly be used for operation over such terrain, their power requirements, and, therefore, energy consumption, are relatively high. In addition, the only type of aircraft which would be potentially suitable are helicopters which themselves could not be landed in much of this terrain. As a result, amphibious air cushion vehicles and buoyant-wheeled vehicles have proven to be very effective for use in these specialized circumstances. Both types of vehicles have very low ground pressure, and neither cause much disturbance to the surface over which they are operating, either from their means of support or propulsion.
The principal drawback of air-cushioned vehicles is the limitation to their grade climbing capability, and their inability to pass from one surface to another where the gradient between the level of the two surfaces exceeds a predetermined amount. These disadvantages are not present with a buoyant-wheeled vehicle which possesses considerable grade climbing capability, and the ability to pass from one surface level to another whether the surfaces be of the same or different materials. These buoyant-wheeled vehicles use low pressure tires, which are in effect trapped air cushions, which reduce ground pressure by increasing footprint area. However, such vehicles have disadvantages in that they have limited increase in footprint area, are expensive to build, replace and service. In addition, the use of such buoyant-wheeled vehicles requires a large single high silhouette casing tire which is difficult to service or replace in the field, and severe damage to such tires requires that the entire unit be replaced and the damaged casing discarded.
A vehicle described herein is capable of utilizing two 7'.times.7' tracks in tandem having 98 sq. ft. of weight bearing area covering almost the entire base of the vehicle. The vehicle will support 6115.2 pounds per foot of immersion in water, that means it will float one foot deep at 6115.2 pounds gross weight. Floating two feet immersed, the tandem 7'.times.7' dual track vehicle will carry 12,230.4 pounds gross weight. At internal track air pressures of 1 p.s.i. The above tandem track vehicle will carry 7 tons and float 27" immersed in water. At track pressures of 2, 3, 4, and 10 p.s.i., the vehicle will carry 14, 21, and 70 tons gross weight respectively.